Delete inaccurate comments

Author: fkm3

tensorflow-ops/src/TensorFlow/Gradient.hs

@@ -444,8 +444,8 @@ gradForBinaryCwise (x, gx) (y, gy) =
   where
     dx = reshape (sum gx rx) sx
     dy = reshape (sum gy ry) sy
-    sx = shape x -- (x :: Tensor Build t)
-    sy = shape y -- (y :: Tensor Build t)
+    sx = shape x
+    sy = shape y
     (rx, ry) = broadcastGradientArgs sx sy
 
 -- | The gradient function for an op type.